This invention is related to a process for the manufacture of alkyd resins and in particular to an improvement in this process.
Conventional processes for the preparation of alkyd resins use an esterification reaction to react a polybasic acid and a polyhydric alcohol, and usually, an esterification catalyst is used. The reaction either uses a solvent or can be accomplished without the presence of a solvent. A problem arises at the completion of the process, since the reaction must be stopped rapidly. One technique that is used is to rapidly dissolve the resin in a solvent for the resin which is at a relatively low temperature, and this stops the reaction. If the reaction is not stopped, the resin will gel, crosslink, and harden in the reaction vessel, and very costly maintenance is required to remove the resin. At present, there is no technique known to reverse gelation of an alkyd resin to remove the resin from the reaction vessel or to make a useable product from a gelled alkyd resin.
The novel process of this invention not only stops the gelation of an alkyd resin, but reverses this gelation to form a composition suitable for use in paints and varnishes.